sysfs.c

   1 /*
   2  * sysfs - extract md related information from sysfs.  Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2009 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software
  20  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  */
  25
  26 #include        "mdadm.h"
  27 #include        <dirent.h>
  28 #include        <ctype.h>
  29
  30 int load_sys(char *path, char *buf)
  31 {
  32         int fd = open(path, O_RDONLY);
  33         int n;
  34         if (fd < 0)
  35                 return -1;
  36         n = read(fd, buf, 1024);
  37         close(fd);
  38         if (n <0 || n >= 1024)
  39                 return -1;
  40         buf[n] = 0;
  41         if (n && buf[n-1] == '\n')
  42                 buf[n-1] = 0;
  43         return 0;
  44 }
  45
  46 void sysfs_free(struct mdinfo *sra)
  47 {
  48         while (sra) {
  49                 struct mdinfo *sra2 = sra->next;
  50                 while (sra->devs) {
  51                         struct mdinfo *d = sra->devs;
  52                         sra->devs = d->next;
  53                         free(d);
  54                 }
  55                 free(sra);
  56                 sra = sra2;
  57         }
  58 }
  59
  60 int sysfs_open(char *devnm, char *devname, char *attr)
  61 {
  62         char fname[50];
  63         int fd;
  64
  65         sprintf(fname, "/sys/block/%s/md/", devnm);
  66         if (devname) {
  67                 strcat(fname, devname);
  68                 strcat(fname, "/");
  69         }
  70         strcat(fname, attr);
  71         fd = open(fname, O_RDWR);
  72         if (fd < 0 && errno == EACCES)
  73                 fd = open(fname, O_RDONLY);
  74         return fd;
  75 }
  76
  77 void sysfs_init(struct mdinfo *mdi, int fd, char *devnm)
  78 {
  79         mdi->sys_name[0] = 0;
  80         if (fd >= 0) {
  81                 mdu_version_t vers;
  82                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  83                         return;
  84                 devnm = fd2devnm(fd);
  85         }
  86         if (devnm == NULL)
  87                 return;
  88         strcpy(mdi->sys_name, devnm);
  89 }
  90
  91 struct mdinfo *sysfs_read(int fd, char *devnm, unsigned long options)
  92 {
  93         char fname[PATH_MAX];
  94         char buf[PATH_MAX];
  95         char *base;
  96         char *dbase;
  97         struct mdinfo *sra;
  98         struct mdinfo *dev, **devp;
  99         DIR *dir = NULL;
 100         struct dirent *de;
 101
 102         sra = xcalloc(1, sizeof(*sra));
 103         sysfs_init(sra, fd, devnm);
 104         if (sra->sys_name[0] == 0) {
 105                 free(sra);
 106                 return NULL;
 107         }
 108
 109         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 110         base = fname + strlen(fname);
 111
 112         sra->devs = NULL;
 113         if (options & GET_VERSION) {
 114                 strcpy(base, "metadata_version");
 115                 if (load_sys(fname, buf))
 116                         goto abort;
 117                 if (strncmp(buf, "none", 4) == 0) {
 118                         sra->array.major_version =
 119                                 sra->array.minor_version = -1;
 120                         strcpy(sra->text_version, "");
 121                 } else if (strncmp(buf, "external:", 9) == 0) {
 122                         sra->array.major_version = -1;
 123                         sra->array.minor_version = -2;
 124                         strcpy(sra->text_version, buf+9);
 125                 } else {
 126                         sscanf(buf, "%d.%d",
 127                                &sra->array.major_version,
 128                                &sra->array.minor_version);
 129                         strcpy(sra->text_version, buf);
 130                 }
 131         }
 132         if (options & GET_LEVEL) {
 133                 strcpy(base, "level");
 134                 if (load_sys(fname, buf))
 135                         goto abort;
 136                 sra->array.level = map_name(pers, buf);
 137         }
 138         if (options & GET_LAYOUT) {
 139                 strcpy(base, "layout");
 140                 if (load_sys(fname, buf))
 141                         goto abort;
 142                 sra->array.layout = strtoul(buf, NULL, 0);
 143         }
 144         if (options & GET_DISKS) {
 145                 strcpy(base, "raid_disks");
 146                 if (load_sys(fname, buf))
 147                         goto abort;
 148                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 149         }
 150         if (options & GET_DEGRADED) {
 151                 strcpy(base, "degraded");
 152                 if (load_sys(fname, buf))
 153                         goto abort;
 154                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 155         }
 156         if (options & GET_COMPONENT) {
 157                 strcpy(base, "component_size");
 158                 if (load_sys(fname, buf))
 159                         goto abort;
 160                 sra->component_size = strtoull(buf, NULL, 0);
 161                 /* sysfs reports "K", but we want sectors */
 162                 sra->component_size *= 2;
 163         }
 164         if (options & GET_CHUNK) {
 165                 strcpy(base, "chunk_size");
 166                 if (load_sys(fname, buf))
 167                         goto abort;
 168                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 169         }
 170         if (options & GET_CACHE) {
 171                 strcpy(base, "stripe_cache_size");
 172                 if (load_sys(fname, buf))
 173                         /* Probably level doesn't support it */
 174                         sra->cache_size = 0;
 175                 else
 176                         sra->cache_size = strtoul(buf, NULL, 0);
 177         }
 178         if (options & GET_MISMATCH) {
 179                 strcpy(base, "mismatch_cnt");
 180                 if (load_sys(fname, buf))
 181                         goto abort;
 182                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 183         }
 184         if (options & GET_SAFEMODE) {
 185                 int scale = 1;
 186                 int dot = 0;
 187                 unsigned i;
 188                 unsigned long msec;
 189                 size_t len;
 190
 191                 strcpy(base, "safe_mode_delay");
 192                 if (load_sys(fname, buf))
 193                         goto abort;
 194
 195                 /* remove a period, and count digits after it */
 196                 len = strlen(buf);
 197                 for (i = 0; i < len; i++) {
 198                         if (dot) {
 199                                 if (isdigit(buf[i])) {
 200                                         buf[i-1] = buf[i];
 201                                         scale *= 10;
 202                                 }
 203                                 buf[i] = 0;
 204                         } else if (buf[i] == '.') {
 205                                 dot=1;
 206                                 buf[i] = 0;
 207                         }
 208                 }
 209                 msec = strtoul(buf, NULL, 10);
 210                 msec = (msec * 1000) / scale;
 211                 sra->safe_mode_delay = msec;
 212         }
 213         if (options & GET_BITMAP_LOCATION) {
 214                 strcpy(base, "bitmap/location");
 215                 if (load_sys(fname, buf))
 216                         goto abort;
 217                 if (strncmp(buf, "file", 4) == 0)
 218                         sra->bitmap_offset = 1;
 219                 else if (strncmp(buf, "none", 4) == 0)
 220                         sra->bitmap_offset = 0;
 221                 else if (buf[0] == '+')
 222                         sra->bitmap_offset = strtol(buf+1, NULL, 10);
 223                 else
 224                         goto abort;
 225         }
 226
 227         if (! (options & GET_DEVS))
 228                 return sra;
 229
 230         /* Get all the devices as well */
 231         *base = 0;
 232         dir = opendir(fname);
 233         if (!dir)
 234                 goto abort;
 235         sra->array.spare_disks = 0;
 236
 237         devp = &sra->devs;
 238         sra->devs = NULL;
 239         while ((de = readdir(dir)) != NULL) {
 240                 char *ep;
 241                 if (de->d_ino == 0 ||
 242                     strncmp(de->d_name, "dev-", 4) != 0)
 243                         continue;
 244                 strcpy(base, de->d_name);
 245                 dbase = base + strlen(base);
 246                 *dbase++ = '/';
 247
 248                 dev = xmalloc(sizeof(*dev));
 249
 250                 /* Always get slot, major, minor */
 251                 strcpy(dbase, "slot");
 252                 if (load_sys(fname, buf)) {
 253                         /* hmm... unable to read 'slot' maybe the device
 254                          * is going away?
 255                          */
 256                         strcpy(dbase, "block");
 257                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 258                             errno != ENAMETOOLONG) {
 259                                 /* ...yup device is gone */
 260                                 free(dev);
 261                                 continue;
 262                         } else {
 263                                 /* slot is unreadable but 'block' link
 264                                  * still intact... something bad is happening
 265                                  * so abort
 266                                  */
 267                                 free(dev);
 268                                 goto abort;
 269                         }
 270
 271                 }
 272                 strcpy(dev->sys_name, de->d_name);
 273                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 274                 if (*ep) dev->disk.raid_disk = -1;
 275
 276                 strcpy(dbase, "block/dev");
 277                 if (load_sys(fname, buf)) {
 278                         /* assume this is a stale reference to a hot
 279                          * removed device
 280                          */
 281                         free(dev);
 282                         continue;
 283                 }
 284                 sra->array.nr_disks++;
 285                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 286
 287                 /* special case check for block devices that can go 'offline' */
 288                 strcpy(dbase, "block/device/state");
 289                 if (load_sys(fname, buf) == 0 &&
 290                     strncmp(buf, "offline", 7) == 0) {
 291                         free(dev);
 292                         continue;
 293                 }
 294
 295                 /* finally add this disk to the array */
 296                 *devp = dev;
 297                 devp = & dev->next;
 298                 dev->next = NULL;
 299
 300                 if (options & GET_OFFSET) {
 301                         strcpy(dbase, "offset");
 302                         if (load_sys(fname, buf))
 303                                 goto abort;
 304                         dev->data_offset = strtoull(buf, NULL, 0);
 305                         strcpy(dbase, "new_offset");
 306                         if (load_sys(fname, buf) == 0)
 307                                 dev->new_data_offset = strtoull(buf, NULL, 0);
 308                         else
 309                                 dev->new_data_offset = dev->data_offset;
 310                 }
 311                 if (options & GET_SIZE) {
 312                         strcpy(dbase, "size");
 313                         if (load_sys(fname, buf))
 314                                 goto abort;
 315                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 316                 }
 317                 if (options & GET_STATE) {
 318                         dev->disk.state = 0;
 319                         strcpy(dbase, "state");
 320                         if (load_sys(fname, buf))
 321                                 goto abort;
 322                         if (strstr(buf, "in_sync"))
 323                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 324                         if (strstr(buf, "faulty"))
 325                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 326                         if (dev->disk.state == 0)
 327                                 sra->array.spare_disks++;
 328                 }
 329                 if (options & GET_ERROR) {
 330                         strcpy(buf, "errors");
 331                         if (load_sys(fname, buf))
 332                                 goto abort;
 333                         dev->errors = strtoul(buf, NULL, 0);
 334                 }
 335         }
 336         closedir(dir);
 337         return sra;
 338
 339  abort:
 340         if (dir)
 341                 closedir(dir);
 342         sysfs_free(sra);
 343         return NULL;
 344 }
 345
 346 int sysfs_attr_match(const char *attr, const char *str)
 347 {
 348         /* See if attr, read from a sysfs file, matches
 349          * str.  They must either be the same, or attr can
 350          * have a trailing newline or comma
 351          */
 352         while (*attr && *str && *attr == *str) {
 353                 attr++;
 354                 str++;
 355         }
 356
 357         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 358                 return 0;
 359         return 1;
 360 }
 361
 362 int sysfs_match_word(const char *word, char **list)
 363 {
 364         int n;
 365         for (n=0; list[n]; n++)
 366                 if (sysfs_attr_match(word, list[n]))
 367                         break;
 368         return n;
 369 }
 370
 371 unsigned long long get_component_size(int fd)
 372 {
 373         /* Find out the component size of the array.
 374          * We cannot trust GET_ARRAY_INFO ioctl as it's
 375          * size field is only 32bits.
 376          * So look in /sys/block/mdXXX/md/component_size
 377          *
 378          * This returns in units of sectors.
 379          */
 380         struct stat stb;
 381         char fname[50];
 382         int n;
 383         if (fstat(fd, &stb)) return 0;
 384         if (major(stb.st_rdev) != (unsigned)get_mdp_major())
 385                 sprintf(fname, "/sys/block/md%d/md/component_size",
 386                         (int)minor(stb.st_rdev));
 387         else
 388                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 389                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 390         fd = open(fname, O_RDONLY);
 391         if (fd < 0)
 392                 return 0;
 393         n = read(fd, fname, sizeof(fname));
 394         close(fd);
 395         if (n < 0 || n == sizeof(fname))
 396                 return 0;
 397         fname[n] = 0;
 398         return strtoull(fname, NULL, 10) * 2;
 399 }
 400
 401 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 402                   char *name, char *val)
 403 {
 404         char fname[50];
 405         unsigned int n;
 406         int fd;
 407
 408         sprintf(fname, "/sys/block/%s/md/%s/%s",
 409                 sra->sys_name, dev?dev->sys_name:"", name);
 410         fd = open(fname, O_WRONLY);
 411         if (fd < 0)
 412                 return -1;
 413         n = write(fd, val, strlen(val));
 414         close(fd);
 415         if (n != strlen(val)) {
 416                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 417                         val, fname, strerror(errno));
 418                 return -1;
 419         }
 420         return 0;
 421 }
 422
 423 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 424                   char *name, unsigned long long val)
 425 {
 426         char valstr[50];
 427         sprintf(valstr, "%llu", val);
 428         return sysfs_set_str(sra, dev, name, valstr);
 429 }
 430
 431 int sysfs_set_num_signed(struct mdinfo *sra, struct mdinfo *dev,
 432                          char *name, long long val)
 433 {
 434         char valstr[50];
 435         sprintf(valstr, "%lli", val);
 436         return sysfs_set_str(sra, dev, name, valstr);
 437 }
 438
 439 int sysfs_uevent(struct mdinfo *sra, char *event)
 440 {
 441         char fname[50];
 442         int n;
 443         int fd;
 444
 445         sprintf(fname, "/sys/block/%s/uevent",
 446                 sra->sys_name);
 447         fd = open(fname, O_WRONLY);
 448         if (fd < 0)
 449                 return -1;
 450         n = write(fd, event, strlen(event));
 451         close(fd);
 452         if (n != (int)strlen(event)) {
 453                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 454                         event, fname, strerror(errno));
 455                 return -1;
 456         }
 457         return 0;
 458 }
 459
 460 int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
 461 {
 462         char fname[50];
 463         struct stat st;
 464
 465         sprintf(fname, "/sys/block/%s/md/%s/%s",
 466                 sra->sys_name, dev?dev->sys_name:"", name);
 467
 468         return stat(fname, &st) == 0;
 469 }
 470
 471 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
 472                        char *name)
 473 {
 474         char fname[50];
 475         int fd;
 476
 477         sprintf(fname, "/sys/block/%s/md/%s/%s",
 478                 sra->sys_name, dev?dev->sys_name:"", name);
 479         fd = open(fname, O_RDWR);
 480         if (fd < 0)
 481                 fd = open(fname, O_RDONLY);
 482         return fd;
 483 }
 484
 485 int sysfs_fd_get_ll(int fd, unsigned long long *val)
 486 {
 487         char buf[50];
 488         int n;
 489         char *ep;
 490
 491         lseek(fd, 0, 0);
 492         n = read(fd, buf, sizeof(buf));
 493         if (n <= 0)
 494                 return -2;
 495         buf[n] = 0;
 496         *val = strtoull(buf, &ep, 0);
 497         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 498                 return -1;
 499         return 0;
 500 }
 501
 502 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 503                        char *name, unsigned long long *val)
 504 {
 505         int n;
 506         int fd;
 507
 508         fd = sysfs_get_fd(sra, dev, name);
 509         if (fd < 0)
 510                 return -1;
 511         n = sysfs_fd_get_ll(fd, val);
 512         close(fd);
 513         return n;
 514 }
 515
 516 int sysfs_fd_get_str(int fd, char *val, int size)
 517 {
 518         int n;
 519
 520         lseek(fd, 0, 0);
 521         n = read(fd, val, size);
 522         if (n <= 0)
 523                 return -1;
 524         val[n] = 0;
 525         return n;
 526 }
 527
 528 int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
 529                        char *name, char *val, int size)
 530 {
 531         int n;
 532         int fd;
 533
 534         fd = sysfs_get_fd(sra, dev, name);
 535         if (fd < 0)
 536                 return -1;
 537         n = sysfs_fd_get_str(fd, val, size);
 538         close(fd);
 539         return n;
 540 }
 541
 542 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 543 {
 544         unsigned long sec;
 545         unsigned long msec;
 546         char delay[30];
 547
 548         sec = ms / 1000;
 549         msec = ms % 1000;
 550
 551         sprintf(delay, "%ld.%03ld\n", sec, msec);
 552         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 553         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 554 }
 555
 556 int sysfs_set_array(struct mdinfo *info, int vers)
 557 {
 558         int rv = 0;
 559         char ver[100];
 560         int raid_disks = info->array.raid_disks;
 561
 562         ver[0] = 0;
 563         if (info->array.major_version == -1 &&
 564             info->array.minor_version == -2) {
 565                 char buf[1024];
 566
 567                 strcat(strcpy(ver, "external:"), info->text_version);
 568
 569                 /* meta version might already be set if we are setting
 570                  * new geometry for a reshape.  In that case we don't
 571                  * want to over-write the 'readonly' flag that is
 572                  * stored in the metadata version.  So read the current
 573                  * version first, and preserve the flag
 574                  */
 575                 if (sysfs_get_str(info, NULL, "metadata_version",
 576                                   buf, 1024) > 0)
 577                         if (strlen(buf) >= 9 && buf[9] == '-')
 578                                 ver[9] = '-';
 579
 580                 if ((vers % 100) < 2 ||
 581                     sysfs_set_str(info, NULL, "metadata_version",
 582                                   ver) < 0) {
 583                         pr_err("This kernel does not "
 584                                 "support external metadata.\n");
 585                         return 1;
 586                 }
 587         }
 588         if (info->array.level < 0)
 589                 return 0; /* FIXME */
 590         rv |= sysfs_set_str(info, NULL, "level",
 591                             map_num(pers, info->array.level));
 592         if (info->reshape_active && info->delta_disks != UnSet)
 593                 raid_disks -= info->delta_disks;
 594         rv |= sysfs_set_num(info, NULL, "raid_disks", raid_disks);
 595         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 596         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 597         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 598         if (info->custom_array_size) {
 599                 int rc;
 600
 601                 rc = sysfs_set_num(info, NULL, "array_size",
 602                                    info->custom_array_size/2);
 603                 if (rc && errno == ENOENT) {
 604                         pr_err("This kernel does not "
 605                                 "have the md/array_size attribute, "
 606                                 "the array may be larger than expected\n");
 607                         rc = 0;
 608                 }
 609                 rv |= rc;
 610         }
 611
 612         if (info->array.level > 0)
 613                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 614
 615         if (info->reshape_active) {
 616                 rv |= sysfs_set_num(info, NULL, "reshape_position",
 617                                     info->reshape_progress);
 618                 rv |= sysfs_set_num(info, NULL, "chunk_size", info->new_chunk);
 619                 rv |= sysfs_set_num(info, NULL, "layout", info->new_layout);
 620                 rv |= sysfs_set_num(info, NULL, "raid_disks",
 621                                     info->array.raid_disks);
 622                 /* We don't set 'new_level' here.  That can only happen
 623                  * once the reshape completes.
 624                  */
 625         }
 626         return rv;
 627 }
 628
 629 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 630 {
 631         char dv[PATH_MAX];
 632         char nm[PATH_MAX];
 633         char *dname;
 634         int rv;
 635
 636         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 637         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 638         if (rv)
 639                 return rv;
 640
 641         memset(nm, 0, sizeof(nm));
 642         dname = devid2devnm(makedev(sd->disk.major, sd->disk.minor));
 643         strcpy(sd->sys_name, "dev-");
 644         strcpy(sd->sys_name+4, dname);
 645
 646         /* test write to see if 'recovery_start' is available */
 647         if (resume && sd->recovery_start < MaxSector &&
 648             sysfs_set_num(sra, sd, "recovery_start", 0)) {
 649                 sysfs_set_str(sra, sd, "state", "remove");
 650                 return -1;
 651         }
 652
 653         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 654         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 655         if (sra->array.level != LEVEL_CONTAINER) {
 656                 if (sd->recovery_start == MaxSector)
 657                         /* This can correctly fail if array isn't started,
 658                          * yet, so just ignore status for now.
 659                          */
 660                         sysfs_set_str(sra, sd, "state", "insync");
 661                 if (sd->disk.raid_disk >= 0)
 662                         rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 663                 if (resume)
 664                         sysfs_set_num(sra, sd, "recovery_start", sd->recovery_start);
 665         }
 666         return rv;
 667 }
 668
 669 #if 0
 670 int sysfs_disk_to_sg(int fd)
 671 {
 672         /* from an open block device, try find and open its corresponding
 673          * scsi_generic interface
 674          */
 675         struct stat st;
 676         char path[256];
 677         char sg_path[256];
 678         char sg_major_minor[8];
 679         char *c;
 680         DIR *dir;
 681         struct dirent *de;
 682         int major, minor, rv;
 683
 684         if (fstat(fd, &st))
 685                 return -1;
 686
 687         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 688                  major(st.st_rdev), minor(st.st_rdev));
 689
 690         dir = opendir(path);
 691         if (!dir)
 692                 return -1;
 693
 694         de = readdir(dir);
 695         while (de) {
 696                 if (strncmp("scsi_generic:", de->d_name,
 697                             strlen("scsi_generic:")) == 0)
 698                         break;
 699                 de = readdir(dir);
 700         }
 701         closedir(dir);
 702
 703         if (!de)
 704                 return -1;
 705
 706         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 707         fd = open(sg_path, O_RDONLY);
 708         if (fd < 0)
 709                 return fd;
 710
 711         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 712         close(fd);
 713         if (rv < 0)
 714                 return -1;
 715         else
 716                 sg_major_minor[rv - 1] = '\0';
 717
 718         c = strchr(sg_major_minor, ':');
 719         *c = '\0';
 720         c++;
 721         major = strtol(sg_major_minor, NULL, 10);
 722         minor = strtol(c, NULL, 10);
 723         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 724                  (int) getpid(), major, minor);
 725         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 726                         fd = open(path, O_RDONLY);
 727                         unlink(path);
 728                         return fd;
 729         }
 730
 731         return -1;
 732 }
 733 #endif
 734
 735 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 736 {
 737         /* from an open block device, try to retrieve it scsi_id */
 738         struct stat st;
 739         char path[256];
 740         DIR *dir;
 741         struct dirent *de;
 742         int host, bus, target, lun;
 743
 744         if (fstat(fd, &st))
 745                 return 1;
 746
 747         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
 748                  major(st.st_rdev), minor(st.st_rdev));
 749
 750         dir = opendir(path);
 751         if (!dir)
 752                 return 1;
 753
 754         for (de = readdir(dir); de; de = readdir(dir)) {
 755                 int count;
 756
 757                 if (de->d_type != DT_DIR)
 758                         continue;
 759
 760                 count = sscanf(de->d_name, "%d:%d:%d:%d", &host, &bus, &target, &lun);
 761                 if (count == 4)
 762                         break;
 763         }
 764         closedir(dir);
 765
 766         if (!de)
 767                 return 1;
 768
 769         *id = (host << 24) | (bus << 16) | (target << 8) | (lun << 0);
 770         return 0;
 771 }
 772
 773 int sysfs_unique_holder(char *devnm, long rdev)
 774 {
 775         /* Check that devnm is a holder of rdev,
 776          * and is the only holder.
 777          * we should be locked against races by
 778          * an O_EXCL on devnm
 779          * Return values:
 780          *  0 - not unique, not even a holder
 781          *  1 - unique, this is the only holder.
 782          *  2/3 - not unique, there is another holder
 783          * -1 - error, cannot find the holders
 784          */
 785         DIR *dir;
 786         struct dirent *de;
 787         char dirname[100];
 788         char l;
 789         int ret = 0;
 790         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 791                 major(rdev), minor(rdev));
 792         dir = opendir(dirname);
 793         if (!dir)
 794                 return -1;
 795         l = strlen(dirname);
 796         while ((de = readdir(dir)) != NULL) {
 797                 char buf[100];
 798                 char *sl;
 799                 int n;
 800
 801                 if (de->d_ino == 0)
 802                         continue;
 803                 if (de->d_name[0] == '.')
 804                         continue;
 805                 strcpy(dirname+l, "/");
 806                 strcat(dirname+l, de->d_name);
 807                 n = readlink(dirname, buf, sizeof(buf)-1);
 808                 if (n <= 0)
 809                         continue;
 810                 buf[n] = 0;
 811                 sl = strrchr(buf, '/');
 812                 if (!sl)
 813                         continue;
 814                 sl++;
 815
 816                 if (strcmp(devnm, sl) == 0)
 817                         ret |= 1;
 818                 else
 819                         ret |= 2;
 820         }
 821         closedir(dir);
 822         return ret;
 823 }
 824
 825 int sysfs_freeze_array(struct mdinfo *sra)
 826 {
 827         /* Try to freeze resync/rebuild on this array/container.
 828          * Return -1 if the array is busy,
 829          * return 0 if this kernel doesn't support 'frozen'
 830          * return 1 if it worked.
 831          */
 832         char buf[20];
 833
 834         if (!sysfs_attribute_available(sra, NULL, "sync_action"))
 835                 return 1; /* no sync_action == frozen */
 836         if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
 837                 return 0;
 838         if (strcmp(buf, "frozen\n") == 0)
 839                 /* Already frozen */
 840                 return 0;
 841         if (strcmp(buf, "idle\n") != 0 && strcmp(buf, "recover\n") != 0)
 842                 return -1;
 843         if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
 844                 return 0;
 845         return 1;
 846 }
 847
 848 int sysfs_wait(int fd, int *msec)
 849 {
 850         /* Wait up to '*msec' for fd to have an exception condition.
 851          * if msec == NULL, wait indefinitely.
 852          */
 853         fd_set fds;
 854         int n;
 855         FD_ZERO(&fds);
 856         FD_SET(fd, &fds);
 857         if (msec == NULL)
 858                 n = select(fd+1, NULL, NULL, &fds, NULL);
 859         else if (*msec < 0)
 860                 n = 0;
 861         else {
 862                 struct timeval start, end, tv;
 863                 gettimeofday(&start, NULL);
 864                 if (*msec < 1000)
 865                         tv.tv_usec = (*msec)*1000;
 866                 else
 867                         tv.tv_sec = (*msec)/1000;
 868                 n = select(fd+1, NULL, NULL, &fds, &tv);
 869                 gettimeofday(&end, NULL);
 870                 end.tv_sec -= start.tv_sec;
 871                 *msec -= (end.tv_sec * 1000 + end.tv_usec/1000
 872                           - start.tv_usec/100) + 1;
 873         }
 874         return n;
 875 }